In a number of surgical procedures, such as ophthalmic procedures, the surgical site is irrigated during operation with a sterile solution, which is then drawn off (aspirated) under suction and collected in a container. In some systems, the vacuum is created in the container and a line from the surgical site leading to the container provides the aspirated fluid flow. The surgeon or a member of the operating staff has instrument controls for on/off control of flow, which controls also include means for instantaneously blocking off flow at a flushing or reflux clamp when vacuum at the surgical site must be terminated.
A number of products for this purpose are available that use different configurations, although they generally employ a container that is insertable in or attachable to the machine, and they are also arranged to reduce the number of attachments that have to be made. Older systems for surgery and ophthalmology were based on the use of separate tubing sections which had to be threaded into the machine, but most later systems incorporate a housing or body with attached or internal tubing, and an associated or attached collector or container. Since the systems must handle body fluids, one objective has been to provide low cost units which can be disposed of after use, which is generally the practice in the United States. In other countries, and with increasing attention to health care costs, some health care facilities prefer sterilization and reuse. In any event, the unit should be as low in cost as is consistent with operative and quality constraints.
One example of such a system is shown in U.S. Pat. No. 4,773,897 to Scheller et al., which is said to be a reusable autoclavable vessel, and is based upon a relatively thin vessel shape which fits into a recess in the machine with which it is to be used. The top wall of the container is specially shaped to provide a vacuum port adjacent its distal end, and includes an interior aspiration port, to which coupling is made by an insert. The insert fits within a recess in the top wall to be flush with the top wall, and the insert also includes a tubing extending in the proximal direction through the front wall of the housing. In order for this to be conveniently useable, the insert includes a breakaway portion and has a configured finger grip at its side. As the container fills, the level of fluid is detected by the system, which has a light path that is interrupted by a float ball contained in an interior chamber within the collector.
In addition to features of convenient connection at low cost, a number of desirable aspects should be provided in addition to the functions of flow control mentioned above. The interior of the chamber in the Scheller et al. device is not conveniently adequately cleaned and sterilized by autoclaving or otherwise, since the only two openings are close together, and the float in the interior chamber is not readily accessible to be cleaned and sterilized. In addition, the system only indicates when the canister is full, but the surgeon may prefer to observe the increase of fluid so that a decision can be made in anticipation of a need for replacement. Also, the system should assure, to the extent possible, that the aspirated fluid is not drawn into the vacuum system, which can happen as the liquid level rises toward the vacuum port. Finally, the system should include secondary means for preventing overfilling of the container in the event of a failure in the optical detection (light path) function.